Heretofore it commonly has been a practice to initially activate a polymeric surface prior to bonding the same to an elastomeric material. For instance, the surfaces of polyethylene terephthalate tire cords commonly are treated so that they will better adhere to the rubber of a tire.
It has been a common practice to use reactive epoxy compounds during the activation of the polymeric surface. Such epoxy compounds are commercially available in which the epoxide groups are preformed and provide an essential component of the molecule. See, for instance, U.S. Pat. Nos. 3,793,425 and 4,044,189 to Robert J. Arrowsmith. Alternatively, one may select an epichlorohydrin ether or ester derived from a polyhydric alcohol or polycarboxylic acid, such as disclosed in U.S. Pat. No. 4,438,178 to Edward J. Powers. However, when this approach is selected, the active ingredient inherently will form a substantial concentration of epoxide groups during use. It has also been proposed in the past to use homopolymers of epichlorohydrin in some adhesive applications.
It is well recognized by those skilled in this technology that any material which is used to activate a polymeric surface should not unduly interfere with the processing and handling of the polymeric material. For instance, it is important that adhesive activated polymeric tire cords be capable of being handled and readily pass through the requisite equipment in the absence of undue adhesion to objects with which they come in contact. Accordingly, such adhesion promoters must be capable of forming an adhesive-activated product which well provides the required adhesion promotion, requisite solubility for ease of application, the absence of excessive tackiness which will interfere with the handling and processing of the surface-activated product, and the absence of excessive buildup of the adhesion promoter on the processing equipment.
In recent years health concerns have been raised with respect to the use of various adhesion-promoting systems of the prior art which rely upon the use of epoxide groups to facilitate the desired adhesion. It is understood that extensive medical testing has indicated that prolonged exposure to very high levels of the adhesion-promoting epoxy compounds can produce adverse health effects in laboratory animals. It further is understood that the testing to date has indicated no human health effects which can be attributed to the adhesion-promoting epoxy compounds. Nevertheless, it has often become a standard practice to adopt worker health-protection measures for the safety of those who may come in contact with the adhesion-promoting epoxy compounds. These have included, the wearing of special clothing, the use of air-filtration masks by workers, the requirement for workers to shower at the conclusion of a work shift, etc.
It is an object of the invention to provide a novel halogenated polyether which is substantially free of epoxy groups.
It is an object of the present invention to provide a novel polyether containing at least one 2-halomethyloxyethylene unit and 2,3-dihydroxypropyl end groups in the substantial absence of epoxy groups (as described).
It is another object of the present invention to provide a novel halogenated polyether which has been found to possess the requisite characteristics for satisfactory service as a promoter of adhesion between a polymeric surface and an elastomeric material.
It is another object of the present invention to provide a novel halogenated polyether which while substantially lacking epoxy groups surprisingly has been found to make possible good adhesion and good processability in the resulting product when used as a promoter of adhesion between a polymeric surface and an elastomeric material.
It is a further object of the present invention to provide a novel halogenated polyether which is believed to be suitable for handling by workers without the need for cumbersome protection measures.
These and other objects and advantages of the present invention will be apparent to those skilled in the art from the following detailed description and appended claims.